In general, hydroprocessing involves the treatment of a feed with hydrogen. The objectives of hydroprocessing vary widely and are a function of the nature of the feed and the process conditions. An important process condition is choice of the hydroprocessing catalyst as nearly all hydroprocessing reactions are catalytic in nature. The typical hydroprocessing reaction involves contacting the feed with a hydroprocessing catalyst at elevated temperature and pressure.
An example of a hydroprocessing reaction is hydrotreating. Hydrotreating itself can have different results/objectives such as hydrodesulfurization (HDS), hydrodenitrogenation (HDN) and hydrodearomatization. In a typical hydrotreating process, a petroleum feedstock that contains an unacceptable level or sulfur and/or nitrogen contaminants is contacted with hydrogen and a hydrotreating catalyst at elevated temperature and pressure. The hydrotreating catalyst may vary according to whether the objective is HDS or HDN and process conditions of temperature and pressure may also change. These catalysts may also possess hydrogenation activity for the saturation of unsaturated hydrocarbons. This latter property may be desirable or undesirable depending on the desired use. It would be highly desirable to have a catalyst activation procedure in which catalyst activity could be increased over conventional activation processes, i.e., those activation processes currently known and practiced by those skilled in the art of hydroprocessing. In the general case, hydrotreating catalysts are activated by converting metal (oxides) present on a catalyst base to a metal sulfide form. Whether these catalysts are freshly made or regenerated, the activation step is an aid in achieving good initial activity and stable activity maintenance (low deactivation rate).
The conventional activation procedure for sulfided catalysts involves heating the (oxidic) catalyst in the presence of a sulfur containing compound, which converts to H2S during the heatup, and the H2S so produced reacts with metal oxides on the catalyst support, resulting in conversion to the active state, metal sulfides. Most often, hydrogen is also present during catalyst activation. The catalyst may be activated while “on oil”.